Extension dock holder



FIG. 1 is a first perspective view of an extension dock holder showing my new design;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top view thereof;

FIG. 8 is a bottom view thereof; and,

FIG. 9 is a perspective view of another state of the extension dock holder thereof.

The broken lines shown in the drawings depict portions of the extension dock holder in which the design is embodied that form no part of the claimed design. 

CLAIM The ornamental design for an extension dock holder, as shown and described. 